I have published first version recipe how to make Exim use LMTP callouts for
verifying validity of addresses in virtual domains of local cyrus IMAP server
(both sender and recipients).
http://anfi.homeunix.net/exim/rtvcyrus.html
It is one of those "simple when you know it" things :-)
Could you authoritatively confirm that Exim can't do callouts over unix
sockets ? ("lmtp" transport with "socket" option")
Such capability seems to be missing in verify.c of exim 4.34.
P.S.
Feel free to send comments and references to "previous art".
--
Andrzej [en:Andrew] Adam Filip anfi@??? anfi@???
http://anfi.homeunix.net/ http://slashdot.org/~anfi